1. Field of the Invention
This invention relates to a retractable/disposable craft knife, and, more particularly, to a knife housing into which a unitary blade and flexible beam assembly is readily retracted and from which the assembly is readily extended. Upon exhausting the service life of the blade, the knife is disposable.
2. Description of the Prior Art
Craft knives are used for a multiplicity of purposes and for most effective use the blade must always be sharp. Convenience, safety, economics, and ergonomics all are factors which also are considered in craft knife utilization.
It is convenient to have a craft knife which is both retractable and disposable. While many craft knives have disposable blades few are manufactured sufficiently economically that the entire knife, upon exhausting the service life of the blade, becomes disposable.
In some occupations, craft knives are used repetitively throughout the workday increasing the importance of ergonomic construction. In terms of craft knives, ergonomic design includes a construct that, when naturally held, results in a blade position normal to the cutting plane and one that enables downward pressure to be readily controlled by the user.
Frequently, a craft knife is a household item and, when retractable, carried about in pocket or purse. Thus, safety considerations include a retraction-extension mechanism that has a safety latch, and, when the safety latch is engaged, stays securely sheathed without unexpected or undesired extensions. While the parameter of disposability is of high interest, the within disclosure includes a description of a blade insert or refill blade and beam assembly for the unique product herein described.
In preparing for this disclosure, several patents became known to inventors hereof. By way of background, the patents to Scheminger et al., U.S. Pat. No. 4,813,143 (Original Classification 30/335; issued Mar. 21, 1989); Abidin et al, U.S. Pat. No. 5,545,175 (Original Classification 606/182; issued, Aug. 13, 1996); and, Wallays, U.S. Pat. No. 5,933,018 (Original Classification 16/114R; issued Aug. 10, 1999) are noted.
Scheminger et al. U.S. Pat. No. 4,813,143—The Scheminger et al. patent describes a knife having an adjustable blade length, the tang of which slides into and out of a sliding chamber within the handle thereof. The portion of the handle surrounding the tang is of a resilient deformable material having a high coefficient of friction which, upon being grasped, secures the adjustable blade in the position of use.
Abadin et al., U.S. Pat. No. 5,545,175—The Abidin et al. patent describes a disposable, guarded finger scalpel, the technical advance of which was in response to the need to reduce exposure to the AIDS virus during surgical procedures. Upon squeezing the sides of the scalpel between the thumb and forefinger, a blade is advanced out of an opening. After making an incision, the release of pressure by the user results in the contaminated blade being withdrawn into the scalpel housing. The device of the invention provides a lock-off so that, after use, the contaminated blade is secured within the housing.
Wallays. U.S. Pat. No. 5,933,918—Wallays '918 discloses a multi-use handle for adaptive use with a variety of inserts, which inserts, in turn, serve as a cutting wheel, brush, or scraper. Each implement clips into the forward end of the handle and has a locking component within the receiving chamber of the handle.
These patents are representative of the present state-of-the-art, but do not singly or in combination exhibit the characteristics of the craft knife and insert therefor presented, infra. The citing of the above patents is not intended as an admission that any such patent constitutes prior art against the claims of the present application. Applicant does not waive any right to take any action that would be appropriate to antedate or otherwise remove any listed document as a competent reference against the claims of the present application.
Other technical problems are overcome or resolved by the invention disclosed herein. The innovative approach becomes apparent in the description which follows.